In the field of adaptive welding, it is of paramount importance to accurately control the weld voltage, wire feed speed, and welding torch travel speed to maintain a desired weld material deposition rate. The cross sectional area of a weld groove is directly tied to the deposition rate and, therefor, it is necessary to precisely determine the groove area and adjust the weld parameters accordingly. Measurements are taken on a periodic basis along the weld groove to account for changes known to occur in weld groove areas. These measurements are accomplished by scanning a sensing element (e.g., optical, inductive, capacative, etc.) along a path extending across the weld groove and detecting the cross sectional configuration. The groove area is then determined from the cross section. This method of controlling fill characteristics has worked well in conjunction with linear weld grooves, consistently filling grooves to the proper level within the physical limitations of the welder and ardently avoiding the obvious problems associated with underfilling a weld groove. However, problems of equal import arise when this system is used on a curvilinear weld groove. In a curved portion of the groove, the actual path scanned by the sensing element will be skewed from the desired scan path which orthogonally traverses the groove. By crossing the groove at a skewed angle, the sensor detects a larger weld groove than actually exists. The erroneously large weld groove causes the system to adjust the welding parameters to an unnecessarily large weld material deposition rate, overfilling the weld grooves.
The denigrating effect of overfilling weld grooves extends beyond the loss of aesthetic value; however, many companies spend tremendous amounts of time, money, and effort on grinding off the excess weld material purely for appearance sake. Further, industries involved in steel fabrication allocate a significant portion of available funds directly to the purchase of consumable weld material. A small percentage savings realized by not overfilling weld grooves translates into a large recurring dollar savings on an annual basis. Moreover, overfilling weld grooves can result in a poor fit between parts and an excessive scrap or rework rate.
The present invention is directed to overcoming one or more of the problems as set forth above.